This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 7 |
| 3 | 41 |
| 4 | 314 |
| 5 | 2194 |
| 6 | 22764 |
| 7 | 195348 |
| 8 | 2374224 |
| 9 | 27940176 |
| 10 | 384636960 |
| 11 | 4673720160 |
| 12 | 95522440320 |
| 13 | 1323221996160 |
| 14 | 23481816503040 |
| 15 | 489968947641600 |
| 16 | 10853692580505600 |
| 17 | 190580382936115200 |
| 18 | 5408424680491929600 |
| 19 | 105077728210820198400 |
| 20 | 3399507785578641408000 |